Pressure responsive diaphragm



May y 1,630,306 H. Y. NORWOOD PRESSURE RESPONSIVE DIAPHRAGM Filed Jan f1.8, 1922 Patented May 31, 1927.

UNITED STATES 1,630,306 PATENT OFFICE.

HARRY Y. NORWOD,. OF ROCHESTER, NEW YORK, ASSIGNOR T0 TAYLOR INSTRUMENT COMPANIES, OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK.

PRESSURE RESPONSIVE DTAPHRAGE.

Application iledlianuary 1S, 1922. Serial No. 530,202.

This invention relates to pressure responsive diaphragms of the variety employed 'tor converting fluid pressure into mechanical motion, having as its chief object the provision of an eflicicnt device of the above character provided with simple and practical means for eectively supporting the Horrible surface or surfaces in an extreme orlimiting position of expansion to prevent distortion or rupture of the same by subjection to eX- cessive pressure. To these and other ends the invention resides in certain improvements and combinations ot parts all as will hereinaftei be more fully described, the

' novel features being pointed out in the claims at the end of the specification.

In the drawings:

Figure 1 is a centra-l sectional View of adevice embodying the present invention and illustrating-'the same at an initial step in manufacture; j t

Figure 2 is a similar view showing a further step with the diaphragms expanded by l pressure Figure 3 isa similar view showing the device completed;

Similar reference numerals throughout the several views indicate the same parts.

rlhe embodiment of the invention selected for the purposes of the present disclosure as best illust-rating the principles involved comprises an expansible pressure responsive lsz.

diaphragm o the so-called wafer type, such as commonly employed. for example, in

' pressure and temperature measuring or regulating apparatus for converting fluid pressure into proportional mechanical movement.. There are employed in the present instance a pair of opposing flexible diaphragms or walls 5 and 6, respectively'l which are preferably formed of disks of resilient sheet metal concentrically corrugated as shown to provide for expansion by pressure admitted between the diapliragms. The latter are connected at their peripheries to complete a fluid tight 'the source of pressure.

by the device, as more fully appears hereafter. rlthe other diaphragm 6 has a central opening, the edges of which embrace and are itted against a shoulder 11 on a plug 12 one end of which extends between the diapl'iragms and is spun over as at 13 on the diaphragm 6 to secure the latter to the plug by a fluid tight connection.` Plug 12 has a threaded reduced portion 14 engaging a correspondingly threaded socket or openin in the end of a coupling member 15 whiclfiy is externally threaded to provide for connection of the same with a conduit leading to pling member 15 have registering channels 16 and 17, respectively, through which the pressure is transmitted between the diaphragms. j i

The present improvements are in this instance embodied in a diaphragm of the above type. although applicable, of course, to various other forms of diaphragm construction, and comprises means. generally speaking, tor uniformly and etlfectively supporting substantially the entire surface of a diaphragm in an expanded position ot' the latter for preventing excessive movement and possible permanent distortion and injury of the diaphragm when subjected to pressures higher than those for which it is designed. As the device with which the invention is combined in the present instance has opposing expansible surfaces, the supporting means comprises a pair of plates 18 and 19 disposed on opposite sides of the diaphragm and supported on the comparatively rigid periphery of the same formed by the laterally projecting portions of the binding strip or idange 7. rllhese plates are preferably constructed of metal having sufiicient thickness and strength to provide substantially rigid walls capable of resisting the outward pressure of the diaphragms. The plates are larger in diameter than the diaphragm so as to extend outwardly beyond the periphery of the saine and their projecting marginal portions are connected by tying means, such, tor example, as the bolts 20 and nuts 21 thereon which serve to clamp the plates securely against opposite sides of the device in spaced relation with the eXpansible portions ot the diaphragms. There are thus formed between plates 18 and 19 .and the adjacent diaphragms, closed recesses which are utilized as moulds for forming the sup- Plug 12 and cou-4 gliY =pose.

phragms. To this end each plate is provided with an opening 22 through which the ma' terial to form the abutment is introduced 1n a fluid state. Such material is preferably oney of the common metal alloys having a low melting point, although of course other substances may be employed for this pur This fluid material for forming the supporting abutment is introduced with the dia-phragms expanded to the extreme or limiting position under which they are intended to operate, 4as shown in Figure 2, and the subsequent setting or hardening ofthe material provides a rigid body having a surface adjacent the corresponding diaphragm which corresponds exactly With the shape of the latter in expanded position and is coextensive therewith, so that the 'diaphragm is effectively supported over its entire surface and in its natural shape.

Before the mould recesses are filled, there is preferably introduced through a central opening 23 in supporting plate 18 a core piece L24@ which is Withdrawn after the casting operation to leave an opening 25 in the castingthrough which may be introduced for contact with the diaphragm the element connecting the latter with the apparatus to be actuated. Also, coupling member 15 is disconnectedl from. plug 12, and a flanged bushing 26 is introduced through an opening` in supporting plate 19 provided to receive coupling member 15 and isfitted about plug 12 to serve as a core providing clearance space between `the cast metal and the plug l2 and coupling 15 vforming the stem of the device. After the metal is poured into this mould sleeve 26 is removed and coupling member 15 reconnected. Preferably the surfaces of the diaphragms and of the sleeve 26 are coated With a film of any suitable substance. such. for example, as petrolatum to prevent ladhesion of the cast metal thereto.

The supporting bodies thus formed, together with the plates 18 and 19 backing the same, serve to provide abutment surfacessubstantially coextensive with the diaphragms and corresponding precisely in shape with the latter in their extreme positions ofexpansion, so that thediaphragms are effectively backed up and supported by a substantially rigid surface of the character fdescribed Which prevents excessive expansion and possible distortion and injury of the diaphragms when subjected to pressures greater than lthose for which the device is designed.

The construction employed is, simple, practical and effective in` character and 4readily and economically applied to' the present and other types of diaphragme and effectively protects the device against inadvertent injury in operation and maintains it in condition for affording, accurate results.

I claim as my invention: `1. In a device of the character described, the combination with a pressure-responsive diaphragm comprising t opposed flexible Walls and a peripheral Wall, of a pair of plates disposed on opposite sides of the iaphragm and interconnected outside the confines thereof to assume a definite position relatively to the diaphragm, and means between the said plates and the said iexible walls, defining surfaces abutting with the flexible Walls over substantially the entire surface thereof when the latter are in a definite expanded condition, said means consisting of material 'cast into the space between the plates and the said flexible Walls While the latterare in expanded condition.

v2. In a device ofthe character described, the combination With a support, a pressure responsive diaphragm having flexible walls l one of which is imperforate and the other provided with anA opening having its edges secured tosaid support, and a laterally projecting rim on said diaphragm, of a pair of plates of greater diameter than said diaphragm having their projecting peripheries formed between said plate and diaphragm lin an expanded position of the latter tol provide an abutment surface conforming in shape tothe diaphragm in said expanded position for limiting the movement thereof.

4: In a device of the character described,

the combination with a pressure responsivel receptacle having opposing flexible walls expansible by lpressure in the receptacle, of plates secured tol said receptacle on opposite sides thereof inl spaced relation with said Walls by means connecting the plates together outside the periphery of the receptacle, and supporting bodies cast between each plate and the adjacent fiexible Wall in an expanded position of the latter for limiting the expansive movement thereof.

HARRY Y. NORWOOD. 

